Combustion control arrangement



1959 E. o. SETTERBLADE 2,899,799

COMBUSTION CONTROL.ARRANGEMENT FOR AFTERBURNERS Filed July 5. 1956 ffoA n/ K United States Patent M COMBUSTION CONTROL ARRANGEMENT FOR AFTERBURNERS Earl O. Setterblade, Stratford, Conn. assignor, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Application July 3, 1956, Serial No. 595,801

1 Claim. (Cl. 6039.72)

This invention relates to a combustion control arrangement for afterburners and more particularly to a fuel pressure responsive bafile construction for stabilizing the burning of fuel in the combustion chamber of an afterburner.

The proper combustion of the fuel in the afterburner zone has been a major problem in jet engines. The velocity of the flame propagation is slow when compared to the velocity of the air in the afterburner chamber. This results in a tendency for the flame to be blown out from the chamber. For a proper burning to obtain maximum thrust, it is essential that the flame be stabilized. A method for stabilizing the burning is to create a turbulence in the air so as to form a vortex in the fluid where the complete burning will take place.

In the instant invention, a plurality of foldable baffle members or flame holders are located downstream of or behind the fuel manifold in the afterburner. When there is afterburning, the baffle members or flame holders are moved to the open or unfolded position in response to a change in fuel pressure so as to cause turbulence and thus the formation of many vortices in the afterburner. This allows for the stabilization of the burning and hence greater thrust. Since the baflle members may be collapsed when not afterburning, there is less drag and hence greater efliciency over all stages of operation.

It is an object of this invention to provide a baflle arrangement for controlling the combustion in an afterburner of a jet engine.

It is a further object of this invention to provide a foldable baffle arrangement for the afterburner of a jet engine to allow for greater efliciency when not afterburnmg.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Figure 1 is a view showing the invention in cross-section.

Figure 2 is a front end view of the mechanism.

Figure 3 is an isometric view of one of the baffle members.

Figure 4 is a partial bottom plan of a cylinder and associated cam mechanism.

Figure 5 is an enlarged section taken along the line VV of Figure 3.

In Figure 1 there is disclosed the combustion chamber housing 1 of the afterburner section of a jet engine. Mounted on the forward end of the housing 1 is a fuel manifold ring 2 carrying fuel ejection tubes 3. Extending along the inner walls of the housing from the manifold ring is a squeal baffle 4. The fuel tubes 3 eject fuel into the hot gases passing through the manifold ring 2 for burning in the combustion chamber 5.

In order to stabilize the burning in the afterburner, a plurality of baflie members or flame holders 6 are mounted in the combustion chamber 5. The flame holders 6 are parallel to and equidistant from each other.

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Each of the flame holders 6 consists of a fixed angle gutter wall 7 and a movable gutter wall 8. The forward end 9 of the fixed gutter wall 7 is rounded to present a streamline portion to the air stream. The opposite ends 10 of the rounded forward end 9 are secured to the'squeal baflle 4. The forward end 11 of the movable gutter wall 8 is also rounded and is secured to the hinge pin 12. The end 11 and the pin 12 are nestled within the rounded end 9 of the fixed gutter. wall for rotation therein. The pin 12 is mounted for rotation in the bearings 13 and 14. The pin 12 extends through the bearing 13 and carries on its end the lever 15.

On the bottom wall of the housing 1, there are mounted by any suitable means (not shown) a plurality of cylinders 16, one for each baifle member or flame holder 6. Each of the cylinders 16 contain a piston 17 for reciprocation in the cylinder. The rod 18 of each piston is operatively connected to a cam member 19 which is pivotally mounted in a U-shaped or three-sided casing 20. The lever 15 is mounted so as to close the open side of the U-shaped casing and bear against the cam 19. The pivotal connection between the gutter Walls 7 and 8 is spring loaded as shown in Figure 5 by a compression spring 24 carried by a pair of projecting guides or retainers 25 and 26 on gutter walls 7 and 8, respectively, to normally maintain the flame holder in a closed position.

The pistons 17 are responsive to changes in afterburner fuel pressure. A line 21 leading from the afterburner fuel pressure line opens into the top of each of the cylinders 16. Each piston 17 is normally urged to a closed position or to the right as reviewed in Figures 3 and 4 by a return spring 22 which may be displaced by the fuel pressure. A bleed 23 in each cylinder 16 allows fuel to escape from the cylinders when non-afterburning.

In operation, the baffle members or flame holders are normally closed. When the throttle is moved to afterburner position, the fuel pressure from the afterburner fuel supply enters the cylinders and actuates the pistons 17. The pistons 17 rotate the earns 19 which move the levers 15 to open the movable gutter walls 8. The gutter walls in the open position stabilize the burning in the afterburner combustion chamber to insure maximum eflioiency. When not afterburning, the return springs 22 automatically move the pistons 17 to allow the flame holders to close.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claim the invention may be practiced otherwise than as specifically described.

What is claimed is:

A combustion control arrangement for a jet engine afterburner comprising an afterburner housing adapted to accommodate the flow of combustible fluids therethrough and having a combustion chamber therein, fuel injection means associated with said afterburner housing and being operable to discharge fuel therein upstream of said combustion chamber, squeal baffle means within said afterburner housing, a plurality of rotatable, spaced and parallel shafts mounted in said housing and extending across the interior thereof, an extremity of each of said shafts protruding through said housing, a plurality of spaced and parallel, fixed, plate-like gutter walls extending across the interior of said housing and secured to said squeal baffle means, a fixed gutter wall having an edge adjacent and parallel to each of said shafts, a plurality of movable plate-like gutter Walls, each of said movable gutter walls having an edge secured to one of said shafts for rotation therewith between open and closed positions relative said fixed gutter walls, resilient means engaging and urging said movable and fixed gutter walls to a normally closed position, a plurality of cylinders carried externally of said of said cylinders to provide a means for bleeding said cylinders, and conduit means connecting each of said cylinders adapted for introducing afterburner fuel pressure into said cylinders to actuate said pistons thereby rotating said shaft-carried movable gutter walls.

References Cited in the file of this patent UNITED STATES PATENTS Hynes et a1. Jan. 1, Harrington et a1 Oct. 8, Oulianolf Dec. 14, Cleveland May 3, Tenney et al. July 16, Karen May 20,

FOREIGN PATENTS Great Britain June 8, 

